Silicon dioxide is one material commonly used as a dielectric in the fabrication of integrated circuitry. Such can be deposited in a number of different manners. One technique includes thermal chemical vapor deposition using precursor gases comprising ozone and TEOS. Such might be conducted under pressure conditions which are atmospheric, subatmospheric, or greater than atmospheric pressure. Silicon dioxide deposited utilizing TEOS and ozone might deposit at uniform rate and thickness over a substrate, or selectively over different areas of the substrate depending upon underlying different materials over which such are deposited, and which might differ in one or more of composition or density.